This invention relates to a liquid crystal antidazzle mirror used for a vehicle.
A liquid crystal antidazzle mirror is used as one type of an antidazzle mirror in an automobile. This liquid crystal antidazzle mirror is constructed as shown in FIG. 3, and has a liquid crystal element 1 disposed in front of a mirror (not shown), a liquid crystal drive circuit 3 for controlling a voltage applied to the electrodes 2a, 2b of the element 1, and a power switch 4 for turning ON and OFF the power source of the drive circuit 3. When the switch 4 is turned ON in case of the use of the antidazzle mirror, power is supplied from a battery 5. The voltage applied to the electrodes 2a, 2b is controlled by operating a mode change switch (not shown) provided in the drive circuit 3 for switching dazzle and antidazzle modes to alter the light transmission rate of the element 1, thereby controlling the reflectivity of the mirror. Thus, the antidazzle mirror performs antidazzling effect for the dazzling light such as the following vehicle.
The abovementioned antidazzle mirror is disposed, for example, as a rear view mirror in a compartment of an automobile. Thus, since the mirror section is ordinarily exposed with the atmospheric air, it can be readily electrically charged. Since the mirror is further contacted to alter the direction of the mirror or wiped off to remove contaminants on the mirror, the liquid crystal element disposed on the front surface of the mirror tends to be electrostatically charged. When the mirror is thus charged electrostatically, the liquid crystal element is adversely affected by the influence of the electrostatic charge to cause the liquid crystal element to be deteriorated in the characteristics for a long period of time. Since the liquid crystal drive circuit for driving the liquid crystal element utilizes an IC which is weak against the static electricity, it causes the liquid crystal element to be damaged in the insulation. The conventional liquid crystal antidazzle mirror is not remedied against such static electricity.